@mRhAnKbOt thanks for running the numbers on rectangle vs round, I wanted to express something similar but didn’t want to do the math
We now know the maximum load the dynamic jaw will take from the testing as it is in direct proportion to the safety shear load on the nut. From this data, the minimum sizes can be calculated for either shape.
This dovetail slide vise is interesting. It is the hardtail design but with the nut at the front.
The idea was to solve the weakness of standard vises when fully open. The front jaw remains fully supported at all times with a moving rear jaw. An advanced solution for 1888.
I dunno if a dovetail like that is technically as strong as the sliding box section of the Fireball vises without being pretty thick. An interesting design for sure though!
I guess if it was tested with the same impact test, then the weight would be swung towards the front jaw. The impact would then also be taken by the body fixed to the bench.
10" of opening is pretty impressive for a vise about 16" long when closed, about 17" shorter than the Fireball & about 23" when open, 24" shorter than the Fireball.
It looks like it can only hold up to 3" thick upright in front of the bench.